Automatic flushing control mechanism



Dec. 17, 1968 M. w. HAMBLEN 3,

AUTOMATIC FLUSHING CONTROL MECHANISM Filed July 11, 1966 2 Sheets-Sheet1 FIG.

FIG. 2

United States Patent 3,416,162 AUTOMATIC FLUSHIN G CONTROL MECHANISMMilton W. Hamblen, Seattle, Wash, assignor to Contamination ControlCorporation, Seattle, Wash., a corporation of Washington Filed July 11,1966, Ser. No. 564,371 6 Claims. (Cl. 4-100) This invention relates toan automatic flushing control mechanism for urinals, toilets, chemicalwaste disposal units, and the like. While the principles of the presentinvention may be used in a variety of applications requiring thegeneration of a control signal upon the occurrence of a predeterminedchange in the electrical properties of a liquid, it will be describedbelow in the context of an automatic flushing control mechanism for alavatory facility.

It is well known that people generally neglect to operate the flushvalves of lavatory facilities in the rest rooms of public places such asfactories, sports arenas, office buildings, etc. In schools, gymnasiums,and other places where young people congregate the problem is often theopposite, as repeated operation of the flush valve after a single use ofthe facility may be the more typical case. Accordingly, rest rooms insuch places oftentimes employ a system providing automatic flushing ofthe lavatory facility at periodic intervals without regard to whetherthe facility has been used and a change of Water is required. Such anarrangement necessarily results in the needless Waste of a largequantity of water. In addition to the expense of this water wastage,there is also the consideration that, in several parts of this countryand in many foreign countries, it is becoming more and more ldiflicultto obtain adequate amounts of water for residential and industrial uses,and therefore massive Water conservation measures are becomingincreasingly necessary.

Automatic flushing mechanisms have been proposed in the past which aredesigned to economize on and prevent this Water usage by replacing thereservoir water in the trap or bowl of the lavatory facility only afteruse of the facility. One device of this type, known to the art, utilizesan electrode assembly situated in the trap or bowl of the urinal orother lavatory facility wherein any change in the specific gravity, andthus the electrical conductivity, of the water, due to contamination byother fluids or soluble foreign matter, unbalances a bridge circuit tothereby provide a control signal for actuating the flush valve of thefacility. Such an arrangement is not entirely satisfactory because anychange in the mineral content of the fresh water supplied to thelavatory facility, as a result of naturally-occurring variations in thelocal Water supply, may on occasion be effective to unbalance the bridgecircuit, and either inhibit its proper operation or cause continuousflushing. Furthermore, elevation or sudden fluctuations in temperaturemay also cause the bridge circuit in such arrangements to spontaneouslyunbalance, thereby generating a false flushing control signal.

The present invention avoids the disadvantages of conventional automaticflushing mechanisms of the type described above by utilizing a pair ofelectrode assemblies situated at different points in the water flowsystem of the facility. One electrode assembly, designated the referencesensor, is located in the fresh water supply \line of the urinal orother lavatory facility. The other sensing element, the measuringsensor, is correspondingly positioned in the trap or bowl of thefacility.

The respective electrode sensors are connected in opposing but otherwiseidentical arms of a Wheatstone bridge circuit which is balanced withfresh water in the facility, so that both electrode assemblies aresensing fluid mediums of identical composition. Thereafter, anycontamination introduced into the tank or bowl of the ice facility willchange the electrical conductivity of the water contained therein.However, since the conductivity of the fresh water in the supply line tothe facility remains unchanged during this time, an imbalance will becreated in the arms of the bridge circuit. The resulting flow of currentbetween the neutra terminals of the bridge is then used as a controlsignal to actuate the flushing valve of the facility and thereby permitfresh water to circulate in the tank. Once the contaminated water isdrained away and replaced with fresh water from the supply line, thebalance in the bridge circuit will be restored, causing the flushingcontrol signal to cut off, and the system restored to its initialcondition.

The advantage of the system disclosed herein is that, since theconductivity of the tank water sensed by the measuring electrode is notcompared to an absolute quantity but instead is referenced against theconductivity of the fresh water supply, any variation in the mineralcontent of the fresh Water supply will be automatically compensated forin the bridge circuit. In addition, any change in the electricalparameters of the circuit components due to temperature effects ordeterioration will not affect the balance of the bridge since both armsof the bridge circuit contain identical components.

In a preferred embodiment of the present invention, the circuit for theautomatic flushing mechanism is arranged so as to permit a plurality oflavatory units to be separately monitored and controlled, using only asingle reference electrode sensor and power supply for the entire systemof units. Any number of lavatory units can be readily added on, asdesired, to the basic control circuit without affecting the operation orincreasing the complexity of the system.

It is therefore a principal objective of the present invention toprovide a novel and improved automatic flushing control mechanism forurinals and other lavatory facilities which initiates flushing actionafter the facility has been used and continues to circulate fresh waterin the facility until the contaminating fluid or other soluble foreignmatter has been removed.

It is another important objective of the present invention to provide animproved automatic flushing control mechanism, of the type comprising anelectrode sensor in a Wheatstone bridge circuit, which is stable inoperation and unaffected by changes in the mineral content oft-he freshwater supply or in the environmental temperature.

And it is another objective of the present invention to provide anautomatic flushing control mechanism of the type described which permitsa plurality of units to be readily added on and separately controlledfrom a central circuit Which requires only a single reference sensor andpower supply for the entire system.

The foregoing and other objectives, features, and ad vantages of thepresent invention will be more readily understood upon consideration ofthe following detailed description of the invention, taken inconjunction with the accompanying drawings.

FIG. 1 is a side elevational view showing an embodiment of the presentinvention providing automatic flushing control of a urinal.

FIG. 2 is a top plan view of the urinal and control unit shown in FIG.1.

FIG. 3 is a top plan view of a pair of urinal units whose flushingaction is separately regulated by a modified embodiment of the automaticflushing control mechanism provided by the present invention.

FIG. 4 is an electrical schematic diagram of a suitable circuitembodiment for providing automatic flushing control of one or morelavatory units according to the present invention.

Referring now ti FIGS. 1 and 2, there will be seen a urinal 10 attachedto a wall 12. At the top of the urinal is a water supply pipeline 14 inwhich is inserted a solenoidactuated flusher valve 16 of conventionaldesign. A box 18 containing the control circuitry (FIG. 4) for actuatingthe valve 16 is mounted to the wall 12. The solenoid of the flushervalve 16 is connected via leads 17 to corresponding terminals 17a on thecontrol box 18 which is energized with electrical power received fromoutlet 20 via cord 19.

At a suitable location in the supply pipe 14 for the urinal 10 issituated the reference electrode sensor 30 comprising a pair of exposedelectrodes projecting in the flow path of the fresh water supply. A pairof lead-in wires 32 connect the reference sensor to correspondingterminals 32a on the control box 18.

In the bottom of the urinal is an exit pipeline 21 leading into agooseneck 22 and thereafter into a discharge line 24. In the gooseneck22 (or other suitable location in the trap of the urinal) is positionedthe measuring sensor 40, similarly comprised of a pair of electrodesprojecting into the fluid collected in the base of the gooseneck. Leadwires 42 from the measuring electrode sensor g connect to correspondingterminals 42a on the control In FIG. 3 the automatic flushing controlmechanism housed in the control box 18 is shown regulating a pair ofurinal units and 10' mounted on a common wall 12. In this modifiedembodiment, elements having the same reference characters as those shownin the embodiment of FIGS. 1 and 2 are identical, and those elementsassociated with the second urinal unit 10 are designated with a primesuperscript. For separate control of two or more lavatory units, thearrangement is identical to that shown in the embodiment of FIGS. 1 and2 except that the reference electrode sensor 30 is inserted in only oneof the fresh water supply pipes 14 since the supply will be common forall of the urinal units. Each of the units 10, 10 has an associatedmeasuring electrode sensor 40, 40' positioned in the gooseneck of itsrespective discharge line, and the flushing of each unit is individuallycontrolled by the electrical circuitry housed in the common control box18.

FIG. 4 shows an electrical schematic of a suitable control circuitry forproviding automatic flushing action of the single or double urinal unitsshown in the embodiments of FIGS. 1-2 and 3, respectively. The circuitshown is capable of providing separate control of up to two lavatoryunits; however, as will be explained below, additional units can bereadily incorporated onto this basic circuitry with a minimum ofcomplexity and expense.

The circuit schematic, for purposes of explanation can be divided intothree major portions: Power Supply Unit #1 Control; and Unit #2 Control.In the Power Supply portion of the control circuit, electrical energy isreceived via cord 19 from a suitable source of alternating potential Ewhich may typically be on the order of 125 volts A.C. This voltage isapplied to the primary P of a power transformer PT having secondarycoils S and S In secondary coil S the alternating waveform is stepped upto a higher potential where one half-wave thereof is first rectified bya diode D and then smoothed by the filter network of R C to provide adirect-current potential E on the order of 170 volts DC The otherhalf-wave of the waveform on the secondary S of the power transformer istapped through a resistance-divider network R R rectified by diode D andthen smoothed by a filter network R C to provide a relatively lowdirect-current potential E on the order of about 4 volts DC. The othersecondary coil S of the power transformer PT supplies a smallalternating voltage E of about 6.3 volts A.C. which, in addition to thefunction described below, may also be used to energize the heaterelements (not shown) of the vacuum tubes employed in the controlcircuit.

Continuing on now to the portion of the electrical diagram designatedUnit #1 Control, the alternating voltage E is applied across theopposing terminals W1, W2

ries with the terminals 42a which are connected to the measuring"electrode sensor 40 in the trap 22 of the first urinal unit. With freshwater in the lavatory facility, and with the sensors 30 and 40 being ofidentical construction and dimension, the currents flowing in therespective left and right-hand branches of the bridge W will be exactlyequal, since the total resistance in the respective branches will beidentical. Accordingly, in this balanced condition, there will be no netvoltage difference appearing across the neutral terminals W3, W4 of thebridge circuit.

Under the above-described balanced state of the bridge circuit W, anegative bias voltage of magnitude E is applied to the grid of thevacuum tube T, by a biasing network comprised of theresistance-capacitance combination R C With this level of negative biasvoltage applied to its grid, vacuum tube T is cut off, and no currentflows in the plate circuit of the tube which is connected through thesolenoid of relay RL to a B+ supply provided by voltage E In the cut-offstate of tube T the contacts 60 of relay RL are in their normally-opencondition and the flusher valve 16 of Unit #1 is disconnected from asource of energizing electrical power E However, when contamination isintroduced into the fresh water collected in the trap of the firstlavatory unit 10 (Unit #1), the conductivity of the current path betweenthe electrodes of the measuring sensor 40 will be significantly changed.This in turn will alter the division of current between the respectivebranches of the Wheatstone bridge circuit W, causing a voltagedifferential to exist across the normally neutral terminals W W4. Thisdifference potential, which is alternating in waveform, unblocks thediode D and causes the bias voltage established across the capacitor Cto leak off. When the negative grid bias has been reduced to apredetermined level, the vacuum tube T will no longer be cut off, andcurrent will start to flow in the plate circuit of the tube.

The flow of current in tube T energizes the solenoid coil of relay RLthus closing contacts 60 and connecting the solenoid of the flushervalve 16 on the first lavatory unit 10 to a source of energizingpotential E Consequently (any contamination introduced into the firsturinal unit 10 unbalances the Wheatstone bridge W and produces a controlsignal, in the form of plate current flow in vacuum tube T for actuatingthe flusher valve of the unit.

Upon actuation of the flusher valve 16, fresh water commencescirculating in the lavatory unit, and the contaminated fluid is dilutedand drained away through the discharge line 24. When the contaminatedwater has been again replaced by fresh water, the conductivity of themeasuring electrode sensor 40 returns to its previous level, and thebalance in the bridge W is restored. This restoration of bridge balancethen blocks the discharge path for the biasing network R C and thecapacitor C commences recharging to the negative bias level establishedby the voltage E whereupon the flow of plate current in the vacuum tubeT is again out off.

Upon the cessation of plate current in tube T relay RL opens itscontacts 60, and the actuation of the flusher valve for Unit #1 isterminated. The control circuit has then completed a full cycle ofoperation, and is ready for response following the next use of thelavatory facility. In this manner flushing action is commenced in Unit#1 each time the water reservoir in the trap of the unit is contaminatedby fluids or other soluble foreign matter, and the flushing continuesuntil the contaminated water is substantially replaced with fresh waterfrom the supply line.

As previously mentioned, the control circuit shown in .nung the 170W offresh when the V nve unit when actuated, of said Voile bridge circuithaving said reference sponding assembly electrically connected in rstindicating branch thereof and having each of said hzeasurin 5 unit hasbe lectro assemblie respectively c nnected in orre ductivit spondinother branches thereolj (e) source of electrical potentia applie crossth two common terminals of said ran h in said NITED bridge circuit, 10

) electrical Inpedan ns 11 1d brid e circuit 1,404,155 1/ 1922 bralancing said bridge or each of the re ective 1,70 1083 4/1929 nitsmaking the current flowing in each said 3101 1119 spectiv ranchescorresponding to a respective unit 0241469 /1 962 ml to e currentflowing in said first branch on- 15 3 115543 12/ 963 mg said referenceelectrode assembly, said bal- 31314, 081 /19 7 Atk COIIdJ ion occurriwhen th Water reservoir 3,373,449 1 usnok respective nit is composedsubstantially VERNE EI E "resh Wate and ectiv m: s erivrn spective con-20 H K ART,

'1al r 12 said bridge for actuating the espec- 5mg cans HSSOCJEitd Wirespecti nit

1. AN AUTOMATIC CONTROL MECHANISM FOR FLUSHING A LAVATORY FACILITY INRESPONSE TO THE CONTAMINATION OF THE WATER THEREIN COMPRISING: (A) FIRSTELECTRODE MEANS SUPPLIED WITH FRESH WATER AND RESPONSIVE TO THEELECTRICAL CONDUCTIVITY THEREOF, (B) SECOND ELECTRODE MEANS SUPPLIEDWITH THE WATER IN SAID FACILITY AND RESPONSIVE TO THE ELECTRICALCONDUCTIVITY THEREOF, (C) FLUSHING MEANS FOR PERMITTING THE FLOW OFFRESH WATER INTO SAID FACILITY WHEN ACTUATED, AND (D) OPERATING MEANSINCLUDING AN ELECTRICAL CIRCUIT CONNECTED TO SAID FIRST AND SECONDELECTRODE MEANS FOR CONTINUOUSLY COMPARING THE CONDUCTIVITY OF THE FRESHWATER SUPPLIED TO SAID FIRST ELECTRODE MEANS WITH THAT OF THE WATER INSAID FACILITY SUPPLIED TO SAID SECOND ELECTRODE MEANS, SAID OPERATINGMEANS PRODUCING AN OUTPUT SIGNAL IN RESPONSE TO A VARIATION BETWEEN SAIDCONDUCTIVITIES TO ACTUATE SAID FLUSHING MEANS.